1. Field of the Invention
The invention relates to a control apparatus, more particularly to a control apparatus capable of resetting a shielding wheel of a stepwise light projecting device to a predetermined starting position when actuated before the light projecting device generates a predetermined stepwise light projecting effect.
2. Description of the Related Art
Referring to FIGS. 1, 2 and 2A, a first conventional light projecting device 10 is shown to include a casing provided with a frontward magnifying lens 18, a driving unit 14 disposed in the casing and supported by a vertical stand 12, a shielding wheel 15 mounted uprightly on a horizontally extending shaft 13 of the driving unit 14, and a light source 11 disposed in the casing and spaced from the shielding wheel 15 in such a manner that light rays emitted by the light source 11 can pass through the wheel 15 and the magnifying lens 18 to an exterior of the casing.
As illustrated, the shielding wheel 15 has a plurality of angularly spaced openings 16 formed therethrough. A plurality of differently colored sheets 17 are attached to the wheel 15 by the use of an adhesive 160 so as to cover the openings 16, respectively. Thus, differently colored rays are emitted to the exterior of the casing upon actuation of the driving unit 14.
A drawback of the aforementioned conventional light projecting device resides in that, after each use, the wheel 15 does not stop at a predetermined starting position. Thus, the wheel 15 must be moved manually so as to dispose the same at the starting position in order to achieve a predetermined light projecting effect. This annoys the user of the light projecting device.
Referring to FIG. 3, a conventional light-projecting device is shown to be similar in structure to the device of FIG. 1, except that a control circuit means is employed (not visible) and that, upon activation of the driving unit 14A, the shielding wheel 15A rotates in a clockwise direction in an initialization mode until an outward protrusion 20 on the wheel 15A collides against a stop element 22 of the driving unit 14A. At this time, the control circuit means activates the shielding wheel 15A to rotate stepwise in the anticlockwise direction in a regular mode to achieve the predetermined light projecting effect.
Note that intermittent collision of the protrusion 20 against the stop element 22 may eventually deform the shaft 13 of the driving unit 14A. In addition, the adhesively mounted colored sheets 17A may loosen or separate from the wheel 15A. Furthermore, the precision of resetting the wheel 15A is relatively poor.